Conventionally, development of an energy management system that performs optimum power management has been taking place in order to efficiently use power supplied from a plurality of power sources, e.g., power from a power system that supplies commercial power, power generated through photovoltaics, and power reserved in a battery.
For example, JP 2012-139019A discloses a configuration of a power conditioner that realizes effective use of generated power by charging a storage battery with the generated power at the time of output suppression control.
FIGS. 1 and 2 show exemplary configurations of an energy management system.
As shown in FIGS. 1 and 2, an energy management system 11 is formed by connecting a power control apparatus 12 to a power system 14 via an ammeter 13, and connecting a photovoltaic (PV) device 15, a battery 16, and an alternating current (AC) load 17 to the power control apparatus 12.
The power control apparatus 12 includes a PV-use DC/DC converter 21, a DC/AC converter 22, a battery-use DC/DC converter 23, and a controller 24. An AC-side terminal of the DC/AC converter 22 is connected to the power system 14 and the AC load 17. On the other hand, a DC-side terminal of the DC/AC converter 22 is connected to the PV device 15 via the PV-use DC/DC converter 21, and to the battery 16 via the battery-use DC/DC converter 23. Hereinafter, wiring which is connected to the DC-side terminal of the DC/AC converter 22 and via which direct current power is supplied between the PV-use DC/DC converter 21 and the battery-use DC/DC converter 23 is referred to as a DC bus 25.
The controller 24 controls the PV-use DC/DC converter 21, the DC/AC converter 22, and the battery-use DC/DC converter 23 in accordance with a condition of the energy management system 11.
In the energy management system 11, as indicated by an arrow A in FIG. 1, the PV-use DC/DC converter 21 applies DC/DC conversion to power generated by the PV device 15 and supplies the resultant power to the DC/AC converter 22 via the DC bus 25, and then the DC/AC converter 22 applies DC/AC conversion to the supplied power and supplies the resultant power to the AC load 17. Excess power is supplied to the power system 14 (reverse power flow).
In a case where the battery 16 is charged with power generated by the PV device 15 via the PV-use DC/DC converter 21, the DC bus 25, and the battery-use DC/DC converter 23, as indicated by an arrow B in FIG. 2, the battery-use DC/DC converter 23 applies DC/DC conversion to the power that is stored in the battery 16 as a result of the charge and supplies the resultant power to the DC/AC converter 22 via the DC bus 25, and then the DC/AC converter 22 applies DC/AC conversion to the supplied power and supplies the resultant power to the AC load 17. Excess power is supplied to the power system 14 (reverse power flow).
With such a reverse flow of power generated by the PV device 15 to the power system 14, the power is sold. A user who owns the power control apparatus 12 can earn a profit from selling the power.
JP 2012-139019A is an example of background art.